For half and reverse line feeds, recognize both SUSv2-style escape-digit

and BSD-style escape-control-char sequences in the input stream.

Submitted by:	schwarze at OpenBSD
Discussed with:	schwarze at OpenBSD
Obtained from:	OpenBSD

2 files changed, 33 insertions, 7 deletions

diff --git a/usr.bin/col/col.1 b/usr.bin/col/col.1
index 9419fe3..fc02ca4 100644
--- a/usr.bin/col/col.1
+++ b/usr.bin/col/col.1
@@ -31,7 +31,7 @@
 .\"     @(#)col.1	8.1 (Berkeley) 6/29/93
 .\" $FreeBSD$
 .\"
-.Dd August 4, 2004
+.Dd May 10, 2015
 .Dt COL 1
 .Os
 .Sh NAME
@@ -82,18 +82,33 @@ recognized and interpreted by itself, which are listed below.
 Output multiple spaces instead of tabs.
 .El
 .Pp
-The control sequences for carriage motion that
+In the input stream,
 .Nm
-understands and their decimal values are listed in the following
-table:
+understands both the escape sequences of the form escape-digit
+mandated by
+.St -susv2
+and the traditional
+.Bx
+format escape-control-character.
+The control sequences for carriage motion and their ASCII values
+are as follows:
 .Pp
 .Bl -tag -width "carriage return" -compact
+.It ESC\-BELL
+reverse line feed (escape then bell).
 .It ESC\-7
-reverse line feed (escape then 7)
+reverse line feed (escape then 7).
+.It ESC\-BACKSPACE
+half reverse line feed (escape then backspace).
 .It ESC\-8
-half reverse line feed (escape then 8)
+half reverse line feed (escape then 8).
+.It ESC\-TAB
+half forward line feed (escape than tab).
 .It ESC\-9
-half forward line feed (escape then 9)
+half forward line feed (escape then 9).
+In
+.Fl f
+mode, this sequence may also occur in the output stream.
 .It backspace
 moves back one column (8); ignored in the first column
 .It carriage return
diff --git a/usr.bin/col/col.c b/usr.bin/col/col.c
index c620bcb..13df126 100644
--- a/usr.bin/col/col.c
+++ b/usr.bin/col/col.c
@@ -205,12 +205,23 @@ main(int argc, char **argv)
 				continue;
 			case ESC:		/* just ignore EOF */
 				switch(getwchar()) {
+				/*
+				 * In the input stream, accept both the
+				 * XPG5 sequences ESC-digit and the
+				 * traditional BSD sequences ESC-ctrl.
+				 */
+				case '\007':
+					/* FALLTHROUGH */
 				case RLF:
 					addto_lineno(&cur_line, -2);
 					break;
+				case '\010':
+					/* FALLTHROUGH */
 				case RHLF:
 					addto_lineno(&cur_line, -1);
 					break;
+				case '\011':
+					/* FALLTHROUGH */
 				case FHLF:
 					addto_lineno(&cur_line, 1);
 					if (cur_line > max_line)